Stripping mechanism



July 3, 11934. J. M. GLASSON STRIPPING MECHANISM Filed June 23,1932 2Sheets-Sheet l INVENTOR I Jo/m ML 6/a550r1 w m A'ITORNEYS Y July 3,1934. M G SSO 1,964,910

STRIPPING MECHANISM Filed June 25, 1932 2 Shee'ts-Sheet 2 f 1 is} I I rI W Q $3 i g I I l 1 INVENTQR n /ko/m M- i/asson MQ M Q Q ATTORNEYSPatented July 3, 1934 STRIPPING MECHANISM John M. Glasson, Johnstown,Pa. Application June 23, 1932, Serial No. 618,901

4 Claims.

This invention relates to stripping mechanism for use in punch pressesand aims to provide means for positively holding the work during thewithdrawal of the punches and subsequently releasing the holding means.

The invention includes means for locking a stripper plate in engagementwith the work, said stripper plate being suspended or otherwisesupported from the movable punch carrier and so arranged that upon thewithdrawal stroke of the punch carrier the stripper plate is unlockedand subsequently moved free of the work. The invention will be fullyapparent from the following specification when read in connection withthe accompanying drawings and will be defined with particularity in theappended claims.

In the drawings- Fig. 1 is an end elevation of so much of a punch pressas is necessary for an understanding of the invention, this view showingthe punches in their fully withdrawn position so that the stripper plateis clear of the work;

Fig. 2 is a view similar to Fig; 1 illustrating the position assumed bythe parts at the limit of the working stroke of the punches;

Fig. 3 is a fragmentary view illustrating an intermediate position ofthe parts during the retracting stroke of the punches and representsthat part of the cycle of operation where the unlocking of the stripperplate is about to take place;

Fig. 4 is a fragmentary side elevation of Fig. 1;

Fig. 5 is a perspective View of the stripper and certain locking dogsassociated therewith;

Fig. 6 is a perspective view illustrative of the type of work piecewhich can be handled by the machine embodying my invention.

Referring in detail to the drawings, 10 represents a fixed bed or baseof a punch press, which may carry any suitable die members. In themachine illustrated, this base has its upper portion shaped to form aseat 12 for the work 14. The work in the case illustrated is a tie platesuch as used for interposing between base flanges and the wooden ties ofordinary railroad tracks. Such tie plates are commonly formed withpunched spike holes 16. The spike holes are adapted to be formed bymeans of punches 18 which are suitably secured to a reciprocatingcarrier 20. This carrier may be actuated by toggle, eccentric, hydraulicpiston or other means commonly employed in the art. The particulardesign of the punch press to which the invention is applied forms nopart of the present invention and hence is not further illustrated. My

improvements may be incorporated in any type of punch press having afixed base and a tool or punch carrier movable relatively thereto.

A particular feature of the invention resides in the improved form ofstripper and in means for locking such stripper in engagement with thefixed base until after the punches have been retracted from the work.

In the embodiment of the invention illustrated,

the stripper indicated as a whole at 22 is in the nature of a plate-likemember having apertures 24 formed therein through which the punches 18are adapted to freely pass.

Dogs 26-26 are pivotally secured by pins 2'7 to the outer ends of thestripper plate 22. dog 26 is provided at its lower end with a tooth 28,which is adapted to engage an abutment 30 formed by slotting out thebase 10. Each dog 26 carries a bracket 32 for supporting a pin 34 Eachwhich passes freely through a lost motion slot 7 36 formed in the lowerextremity of a link 38, which is suspended from the punch carrier 20 bymeans of a pivot pin 40 secured in a bracket 42 carried by the punchcarrier.

In the normal operation, when the punch press is at rest the carrier 20and its punches will be in the elevated position of Fig. 1. This willpermit of readily placing the work piece 14 on the lower die or base ofthe machine. In this position, the

stripper 22 is suspended from the carrier by the 34 secured to thelocking dogs at this time engaging the lower end of the lost motionslots 36. The pivotal movement or" the dogs 26 at this time is limitedby means of interlinks 38, the pins engaging projections 44 and 46formed respectively on the dogs 26 and the stripper 22. As the carriermoves down, the stripper plate 22 together with the dogs 26 will movedownwardly, the parts remaining in the position of Fig. 1

until the stripper plate contacts with the upper face of the work 14.

Continued downward movement of the carrier 20 at this time will permitthe dogs 26 to swing inwardly until their respective teeth 28 move intoengagement with on the fixed base. At the completion of the downwardmovement of the carrier 20, the upper extremities of the slots 36 willengage the pins 34, thus positively insuring that the dogs properlyengage the abutments 30. In this position of 105 the parts, the puncheswill have already pierced the work.

In punching heavy work, such as tie plates and the like and especiallywhere several punches are employed, it is important that when thepunches 1 0 the abutments 30 formed are retracted that the work shallnot move outwardly with the punches. With the improved strippermechanism herein shown, it will be noted that the work is positivelylocked to the fixed base 10 of the punch press. The work remains solocked until the punches on their upward stroke move clear of the upperface of the work or substantially to the position illustrated in Fig. 3.The parts are so designed and arranged that after the punches do theirwork the locking dogs will be automatically disengaged from the base.

In the embodiment of the invention illustrated, when the punches clearthe work on the upward stroke of the carrier the lower extremity of theslot 36 comes into engagement with the pin 34 of the dog, as indicatedin Fig. 3, whereupon a continued upward or retracting movement of thepunch carrier will rock the dogs outwardly so as to disengage them fromthe abutments 30. Continued upward movement will bring the lugs 46 and44 into engagement whereupon during the remainder of the upstroke thestripper will travel upwardly with the carrier, thus returning the partsto the starting position of Fig. l, whereupon the work previouslypunched can be removed by hand or otherwise and a new piece inserted.

From the foregoing, it is clear that the invention provides an extremelysimple yet effective stripper which can be manufactured at low cost andyet perform its function in a positive manner. The stripper parts areadvantageously supported or suspended from the movable punch carrier,thus the stripper and its operating parts form a unit which moves thepunch carrier. This leaves the bed of the machine entirely unobstructed,thereby facilitating the insertion and removal of the work pieces.

While I have described quite precisely the details of the embodiment ofthe invention illustrated it is to be understood that variousmodifications may be made by those skilled in the art without departurefrom the invention as defined in the appended claims.

What I claim is:-

1. In combination with the fixed base and the movable punch carrier andpunch of a punch press, a stripper, locking dogs pivoted to saidstripper, and supporting links for said stripper pivotally suspendedfrom said carrier and having a pin and slot connection with bracketsdetachably secured to said dogs.

2. In combination with the fixed base and the movable punch carrier andpunch of a punch press, a stripper, locking dogs pivoted to saidstripper and adapted to engage said base, swingable links pivotallysuspended from said carrier and having a pin and slot connection withbrackets removably secured to said dogs.

3. In combination with the fixed base and the movable punch carrier andpunch of a punch press, a stripper, locking dogs pivoted to saidstripper and adapted to engage said base, swingable links pivotallysuspended from said carrier and having elongated slots adjacent theirswingable ends, said dogs carrying detachable brackets having pinssecured thereto which pass through the slots in said links.

4. In combination with the fixed base and the movable punch carrier andpunch of a punch press, a stripper, locking dogs pivoted to saidstripper and adapted to engage said base, links having a pivotalmounting on said carrier, and brackets detachably secured to said dogsand having a pin and slot connection with said links.

JOHN M. GLASSON.

